1. Field of the Invention
The present invention pertains to methods and apparatus for testing ball eccentricity and locating the dynamic axis of a sphere and is more particularly directed to method and apparatus for testing and marking a ball such that a player is able to propel the ball with its eccentricity located to accommodate motion along the intended path of travel.
2. State of the Prior Art
Traditionally golf balls have been manufactured by winding a ribbon of resilient material in multiple layers about a hard central core and then encapsulating the windings in a hard outer shell. More recent methods of golf ball manufacture have sought to eliminate the winding process in favor of molding processes whereby a solid spherical layer of a resilient material is molded about a central core. The resilient layer is then encapsulated in the conventional outer shell.
In accordance with the present invention, it has been discovered that in various manufactures, golf balls sometimes exhibit unpredictable dynamic characteristics even when stroked in a consistent manner. For example, an unpredictable ball can be detected by stroking it on a level putting green with a mechanical plunger device capable of delivering a repeatedly uniform stroke. To varying degrees, the golf ball may deviate unpredictably from the expected straight travel path.
At the present time, it is theorized that the unpredictable behavior of a golf ball is often due to an imperfection of balance, namely an eccentricity in the ball. Such inaccuracy of balance occurs in a golf ball having a center of gravity offset from the geometric center of the ball. Consequently, when such a ball is rolled over a surface, forces develop causing the ball to deviate from a straight line of travel. To attain the truest path of travel, an eccentric ball is to be struck such that the dynamic axis tumbles as the ball turns. When a golf ball is randomly stroked during normal play, the undesirable deviations considered above may well hinder competitive play. Consequently, in accordance with the present invention, a need exists for a system to effectively test balls and mark them for more consistent movement.